That’s a valid point and something I did consider. A single parent undergoing IVF clearly has financial capacities which would be preferable to someone struggling to make ends meet. For example, a wealthy single parent may be more capable of buying quality food, sending their child to a good school, and ideally, being able to take time off work in the early years to build a strong bond.
But I’m of the belief that two parents of average income are preferable to one parent with exorbitant income.
Having parents that are in a healthy relationship helps to model what a child should aspire to, as well as giving the child an understanding of the dynamics between men and women. Fathers and mothers both bring unique perspectives and insights into parenting and life and having access to both of these perspectives gives children the best foundations for life. Children of single parents often report a lower quality of life and are less likely to be in a stable relationship themselves.
Additionally, no matter the wealth of the single parent, it’s likely they’ll want to date people at some point in the child's life, and this may involve the introduction of a partner or several over the course of years, which adds additional instability to the childs perception of the world.
Lastly, just on an a priori, intuitive level, I feel a child brought into the world with one parent will always wonder where the other half of their DNA came from.